South East Queensland
Table 1 shows that there is a surplus of available water assets over water liabilities and future commitments that are expected to be settled within 12 months of the reporting date.
|Total water assets as at 30 June 2011||2,231,797|
|Less water assets not available to be accessed, taken or delivered:|
|Less total water liabilities as at 30 June 2011||12,234|
|Less future water commitments expected to be settled within 12 months of the reporting date|
|Expected diversion of supplemented surface water allocations (urban water system)||202,618|
|Expected diversion of surface water allocations (individual users)||5,905|
|Expected diversion of unsupplemented surface water (urban water system)||7,458|
|Expected diversion of unsupplemented surface water (individual users)||2,050|
|Expected diversion of other surface water (individual users)||3,628|
|Expected extraction of groundwater allocations (individual users)||1,113|
|Expected extraction of other groundwater (urban water system)||213|
|Expected extraction of other groundwater (individual users)1||2,266|
|Surplus / (deficit) of available water assets over water liabilities and future water commitments expected to be settled within 12 months of the reporting date||1,983,304|
- Extractions from the 'Non–Benefitted Area' of the Central Lockyer Groundwater Management Area were not available for the 2010–2011 year and as such data have been provided from the 2009–2010 year.
The expected diversions and extractions are based on abstractions made during the current reporting period, which may be lower than normal due to the wet year, and decreased irrigation and outdoor urban demand. Record floods occurred in January 2011, which combined with the very wet year in general (refer to the Climatic overview) resulted in a large volume of water stored within the surface water storages within the region. Despite there being a surplus of available water to meet water liabilities and future commitments, it is expected that additional rainfall and runoff will supply much of the future commitments in the 2011–12 year. If high storage volumes persist into 2011–12, it is expected that the water sharing rules in the Moreton, Logan Basin and Gold Coast resource operation plan will result in 100% allocation announcement for all water supply schemes within the region for the 2011–12 year.
Contingent water assets and water liabilities
The purpose of this note is to report on possible water assets and possible water liabilities for the South East Queensland (SEQ) region. Possible (or contingent) water assets and water liabilities arise from past events and may be confirmed if future events not fully under the control of the management of the region occur.
b. Contingent water assets
The Gold Coast Desalination Plant officially became part of the SEQ Water Grid on 30 September 2011 when it was handed over to WaterSecure (part of Seqwater since July 2011). Desalinated water from the Gold Coast Desalination Plant, in Tugun, is blended with other water supplies before it joins the SEQ Water Grid. The SEQ Water Grid Manager works closely with all entities to determine the demand on the desalination plant through a grid instructions process. Under normal operating conditions, it was planned for the desalination plant to operate at a minimum of 33% capacity (44 ML/day) in accordance with rules outlined in the SEQ System Operating Plan v3.1. With the SEQ region's dams full or near full, the SEQ Water Grid has been operating in 'hot stand–by' mode to minimise operating costs since December 2010. Under this mode of operation, the plant will typically produce around 25 ML/day of water two days a week, with no production in between. This small amount of production is needed to keep the membranes wet and the water in the pipes fresh, while retaining the capacity to ramp up to produce 44 ML/day (33%), 88 ML/day (66%) or 133 ML/day (100%) within hours whenever required.
The plant may be called on if there are interruptions to supply in other parts of the SEQ Water Grid, as occurred in the January floods and in lighting strikes that temporarily knocked out the Mount Crosby Water Treatment Plant. The plant will also cover production when other parts of the Water Grid are offline for routine maintenance or due to water quality issues.
The contingent water asset associated with the Gold Coast Desalination Plant is the difference between the maximum operating capacity (133 ML/day) and the minimum operating rate (7 ML/day average based on hot–standby mode) and equates to 126 ML/day.
The non–extractable portion of groundwater
The groundwater management area (GMA) of the Lockyer Valley located within the Moreton Water Resource Plan (WRP) area was the only aquifer included as a store in the water accounting statements. Within the Benefitted Area of the Central Lockyer Valley Water Supply Scheme (WSS), a groundwater limit exists, which defines the entitled maximum volume that can be extracted from the Benefitted Area of the aquifer as 9,340 ML.
The remaining portion of the groundwater within the Lockyer Valley and all other groundwater within the SEQ region is considered a contingent water asset.
A model was developed within the former Queensland Department of Environment and Resource Management (DERM) to estimate the total volume of water in Implementation Area 1 of the Lockyer Valley GMA. This model is now managed by the Queensland Department of Natural Resources and Mines and/or the Queensland Department of Energy and Water Supply. The total volume of water in Implementation Area 1 was computed by the model to be 102,345 ML at 30 June 2011, an increase of 24,466 ML on 30 June 2010 total volume of 77,879 ML.
Groundwater aquifers do occur elsewhere within the SEQ region. DERM is investigating methods to estimate aquifer storage volumes and it is anticipated that estimates will become available in future water accounts.
It is possible that a change in circumstances, including legislative or regulatory changes that alter the extraction limits, such as the setting of volumetric extraction limits within the Non-Benefitted Area of the Lockyer Valley groundwater aquifer, would result in further portions of the groundwater being included as an asset. There is no estimate available of the total volume stored in groundwater aquifers of the region.
Inter-region claim on water sources within the SEQ Water Grid
The SEQ Water Grid extends outside the National Water Account's 2011 Account SEQ region in the north and east. It includes part of the Mary WRP area (Sunshine Coast) and Stradbroke Island. Entitlements for both supplemented and unsupplemented surface water and groundwater are held by the SEQ Water Grid Manager in the Mary WRP area and Stradbroke Island. Water diverted or extracted based on these entitlements may, after treatment, be transferred into the SEQ region. As the volume transferred into the SEQ region will be determined by within region resources, consumer demand and operational policy of the SEQ Water Grid, water diverted or extracted on these entitlements would be considered a contingent water asset for the SEQ region. As it is unknown what proportion of the entitlements can or may be transferred into the region, an estimate of the contingent water asset can not be made.
c. Contingent water liabilities
Water for urban use (217,755 ML)
Urban retailers within the SEQ region, including Allconnex Water, Queensland Urban Utilities, Unitywater and various regional councils, supply potable water to residential customers throughout the region. These urban retailers maintain water within their distribution pipes for the delivery of water to customers but the actual delivery of water is determined by the customers when they turn on the tap. Therefore the delivery of potable water to customers within the SEQ region is considered a contingent liability. During the 2010–2011 year, 187,339 ML of potable water was supplied to customers of the SEQ Water Grid, 7,458 ML of potable water was supplied to off–grid customers, 21,579 ML of recycled water was supplied to customers within the SEQ region and 1,379 ML of recycled water was supplied to customers outside the SEQ region. Notwithstanding any major changes, it is estimated that a similar volume of water will be required to be delivered in the next reporting period.
Surface water and groundwater water for private use
The resource operation licence holders (Seqwater and Toowoomba Regional Council) allocate water to non–urban supplemented entitlement holders. However, the actual delivery of the water is contingent on the customers when they divert the water. Therefore the delivery of non-urban supplemented water to customers within the SEQ region is considered a contingent liability. During the 2009–2010 year more than 20,000 ML of supplemented surface water was delivered to customers, but in the 2010–2011 year only 6,000 ML of supplemented surface water was delivered to customers due to the wet year (line item 17.7 Non-allocated diversions to users and line item 18.8 Non-allocated extractions to users). Similarly for groundwater, during the 2009–2010 year more than 2,800 ML was delivered to the Benefitted Area of the Central Lockyer WSS compared to 1,113 ML in 2010–2011. It would be expected that the volume supplied during the 2011–2012 year would be greater than 2010–2011 but less than 2009–2010.